The present invention relates to a recording and reproducing apparatus and a recording and reproducing method for recording information on an information recording medium with use of a semiconductor laser.
Information recording is carried out on various types of optical discs. Only once writable optical discs include CD-R, DVD-R, DVD+R, and BD-R. Several-times-writable optical discs include CD-RW, DVD-RAM, DVD-RW, DVD+RW, and BD-RE.
In the technical development of optical disc recording and reproducing apparatuses, the wavelength of a semiconductor laser has been made short and the recording film characteristic of an optical disc as a recording medium has been improved. Through such technical development, data of 25 GB per layer in the recording film of the disc can be recorded on the disc in a BD (Blu-ray Disc) system using a blue laser. In the BD system, a modulation system using the shortest mark length of 2T is employed as a data modulation system.
As techniques relating to a recording and reproducing method, a technique relating to recording waveform is known, for example, in JP-A-2005-35328, and a technique relating to recording power is known, for example, in JP-A-2006-172667.